Test cells for an unprogrammed OTP memory array
AssigneeSidense Corp.
InventorWlodek Kurjanowicz
Life of this patent
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Abstract
Test cells are included in a one-time programmable (OTP) memory array for detecting semiconductor fabrication misalignment, which can result in a potentially defective memory array. The test cells are fabricated at the same time as the normal OTP cells, except they are smaller in size along one dimension in order to detect mask misalignment along that dimension. Any fabricated test cell which cannot be programmed indicates a level of fabrication mask misalignment has occurred and the OTP memory array should not be used.
Claims20
A one time programmable (OTP) memory array comprising:
- rows of unprogrammed OTP cells, each of the unprogrammed OTP cells having a first active area;
- and,
- a row of unprogrammed test OTP cells, each of the unprogrammed test OTP cells having a second active area smaller than the first active area.
A method for testing an unprogrammed OTP memory array having unprogrammed normal OTP cells and unprogrammed test OTP cells, comprising:
- executing a program operation on at least one unprogrammed test OTP cell;
- detecting successful or unsuccessful programming executed on the at least one unprogrammed test OTP cell;
- and,
- determining that the unprogrammed OTP memory array is defective when the at least one unprogrammed test OTP cell is detected to be unsuccessfully programmed.
Dependencies are inferred from the claim text.